After 10 years of black hole science, Stephen Hawking proven right

"In the ten years since then, scientists have detected hundreds of black holes coming together, as well as other extreme cosmic events like neutron stars colliding and black holes merging with a neutron star. Now, in the journal Physical Review Letters, researchers say their ability to analyze gravitational waves has improved so much over the past decade that they were recently able to verify a key idea about the growth of black holes one put forth by Stephen Hawking back in 1971."

""There's a very famous statement in physics that Stephen Hawking worked out, which is that the area, the surface area, of black holes can never decrease," explains Maximiliano Isi, an astrophysicist with Columbia University and the Flatiron Institute. And he says that's just what scientists observed after analyzing gravitational waves detected earlier this year. On January 14, detectors registered gravitational waves that came from two colliding black holes about 1.3 billion light-years away."

""Because the detectors are so much better today, we can record the signal so much more clearly," says Katerina Chatziioannou, a gravitational wave physicist at Caltech. That allowed them to perform a new analysis showing that between the two of them, the initial black holes had a combined surface area of 240,000 square kilometers (roughly the size of Oregon). After they merged to form a"

On January 14 gravitational-wave detectors registered signals from a merger of two black holes about 1.3 billion light-years away. The colliding black holes had masses between 30 and 40 times the Sun, producing a waveform similar to the first detection in 2015. Upgrades to the LIGO detectors significantly improved signal clarity, enabling more precise analysis. The two initial black holes had a combined surface area near 240,000 square kilometers. The surface area of the final, merged black hole did not decrease relative to the initial total, providing observational confirmation of Stephen Hawking's 1971 area theorem. Hundreds of gravitational-wave events have been observed since 2015.

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